High heat conductive insulated substrate and method of manufacturing the same

Abstract

An insulated substrate having high thermal conductivity comprising a substrate having a thermal conductivity of not less than 50 W/m.k., and an insulating layer having high thermal conductivity coated on the substrate; and a method of producing the insulated substrate characterized in that an insulating layer is formed on a substrate by applying DC voltage and RF power to the substrate and providing a magnetic field parallel to the surface of the substrate. The insulated substrate has good heat conductivity, thermal resistance and smooth surface, whereby exfoliation can be prevented.

What we claim is: 
     
       1. An insulated substrate having high thermal conductivity, comprising a metal substrate having a heat conductivity of not less than 50 W/m.k., and at least one insulating layer having a high thermal conductivity coated on the substrate, wherein said insulating layer has a thermal conductivity of not less than 50 W/m.k. and is selected from the group consisting of hard carbon material containing 0.01 to 20 atomic % of at least one element of group IVA deposited on the metal substrate by a plasma method or ion deposition method. 
     
     
       2. The insulated substrate of claim 1, wherein the metal substrate is selected form the group consisting of Cu, Cu alloy, Al, Al alloy, W, W alloy, Zn, Zn alloy, Ni and stainless steel. 
     
     
       3. The insulated metal substrate of claim 1, wherein the hard carbon material is selected from the group consisting of diamond and diamond-like carbon. 
     
     
       4. The insulated substrate of claim 3, wherein the diamond-like carbon contains not more than 9 atomic % of at least one element selected from the group consisting of Si and Ge. 
     
     
       5. The insulated substrate of any one of claims 3 and 4, wherein the thickness of the insulating layer is 10 Å to 2,000 Å. 
     
     
       6. The insulated substrate of any one of claims 1 to 3, wherein the insulating layer has an electrical resistivity of not less than 10 8  Ω·cm and a thermal resistance of 20 V/μm. 
     
     
       7. The insulated substrate of any one of claims 1 to 3, wherein the heat conductivity of the insulated substrate is not less than 50 W/m.k. 
     
     
       8. The insulated substrate of any one of claims 1 to 3, wherein the heat conductivity of the insulated substrate is not less than 100 W/m.k. 
     
     
       9. The insulated substrate of any one of claims 1 to 3, wherein the surface Vickers hardness of the insulated substrate is not less than 500. 
     
     
       10. The insulated substrate of any one of claims 1 to 3, wherein the surface of Vickers hardness of the insulated substrate is not less than 1500. 
     
     
       11. The insulated substrate of claim 1, wherein the elements of group IV A  is at least one element selected from the group consisting of Si, Ge and Sn. 
     
     
       12. An insulated substrate having high thermal conductivity, comprising a substrate having a thermal conductivity of not less than 50 W/m.k., and a multi-layer insulating film provided on the substrate, wherein said multi-layer insulating film has a thermal conductivity of not less than 50 W/m.k. and comprises a layer of at least one material selected from the group consisting of diamond and diamond-like carbon and a layer of silicon carbide. 
     
     
       13. The insulated substrate of claim 12, wherein the substrate comprises crystalline silicon. 
     
     
       14. The insulated substrate of claim 12, wherein the substrate comprises nitrated or oxidized crystalline silicon. 
     
     
       15. The insulated substrate of claim 12, wherein the substrate comprises metal. 
     
     
       16. The insulated substrate of claim 15, wherein the metal substrate is selected from the group consisting of Cu, Cu alloy, Al, Al alloy, W, W alloy, Zn, Zn alloy, Ni and stainless steel. 
     
     
       17. The insulated substrate of claim 12, wherein the diamond-like carbon contains not more than 9 atomic % of at least one element selected from the group consisting of Si and Ge. 
     
     
       18. The insulated substrate of claim 12, wherein the thickness of the layer of diamond or diamond-like carbon is 10 Å to 2,000 Å. 
     
     
       19. The insulated substrate of claim 12, wherein the thickness of the layer of silicon carbide is 10 Å to 1,000 Å and not less than two layers of silicon carbide are formed. 
     
     
       20. The insulated substrate of claim 12, wherein the insulating layer has an electrical resistivity of not less than 10 8  Ω·cm and a thermal resistance of 20 V/μm. 
     
     
       21. The insulated substrate of claim 12, wherein the heat conductivity of the insulated substrate is not less than 50 W/m.k. 
     
     
       22. The insulated substrate of claim 12, wherein the heat conductivity of the insulated substrate is not less than 100 W/m.k. 
     
     
       23. The insulated substrate of claim 12, wherein the surface Vickers hardness of the insulated substrate is not less than 500. 
     
     
       24. The insulated substrate of claim 12, wherein the surface Vickers hardness of the insulated substrate is not less than 1500. 
     
     
       25. The insulated substrate of claim 12, wherein the dielectric constant and dielectric loss at 1 MHz of the insulated substrate are not more than 20 and not more than 0.02, respectively. 
     
     
       26. The insulated substrate of claim 14, wherein the nitrated or oxidized crystalline silicon substrate is obtained by making through holes in a crystalline silicon substrate and thereafter nitrating or oxidizing the substrate. 
     
     
       27. The insulated substrate of claim 14, wherein the nitration or oxidation takes place in the crystalline silicon substrate at least to a depth of 0.1 μm from the surface of the substrate. 
     
     
       28. The insulated substrate of claim 14, wherein the nitration or oxidation takes place in the crystalline silicon substrate at least to a depth of 0.5 μm from the surface of the substrate. 
     
     
       29. The insulated substrate of claim 14, wherein the thickness of the insulating layer is 0.5 to 10 μm. 
     
     
       30. The insulated substrate of claim 14, wherein the thickness of the insulated layer is 1 to 10 μm. 
     
     
       31. The insulated substrate of any one of claims 12, 51 and 52, wherein the electrical conductivity of the insulating layer is not more than 10 -6  Ω -1  cm -1 . 
     
     
       32. The insulating substrate of claim 12, wherein the heat conductivity of the substrate is not less than 50 W/m.k. and the heat conductivity of the insulated substrate is not less than 45 W/m.k. 
     
     
       33. The insulated substrate of claim 12, wherein the electrical resistivity and dielectric breakdown voltage of the insulating layer are not less than 10 12  Ω·cm and not less than 100 V/μm respectively. 
     
     
       34. The insulated substrate of claim 12, wherein the silicon carbide is single crystalline, polycrystalline, microcrystalline or amorphous, wherein said amorphous silicon carbide contains not more than 30 atomic % of at least one element selected from the group consisting of hydrogen and elements from the halogen group. 
     
     
       35. An insulated substrate having high thermal conductivity, comprising a substrate having a heat conductivity of not less than 50 W/m.k., and at least one insulating layer having a high thermal conductivity, wherein an interlayer comprising a metal or an amorphous material having a small coefficient of thermal expansion is provided on at least a portion of the substrate, and the insulating layer is provided on said interlayer, said insulating layer having a thermal conductivity of not less than 50 W/m.k. and being selected from the group consisting of (1) hard carbon material selected from the group consisting of diamond, diamond-like carbon, silicon carbide and germanium carbide; (2) silicon-containing non single crystalline material selected from the group consisting of silicon carbide, silicon nitride, silicon germanium, silicon germanium carbide, and silicon carbide oxide; (3) cubic BN; (4) hexagonal BN; (5) AlN; and (6) BP, wherein said hard carbon material contains 0.01 to 20 atomic % of at least one element of group IVA, and said non single crystalline silicon carbide contains not more than 30 atomic % of at least one element selected from the group consisting of hydrogen and elements of the halogen group. 
     
     
       36. The insulated substrate of claim 35, wherein the substrate comprises crystalline silicon. 
     
     
       37. The insulated substrate of claim 35, wherein the substrate comprises nitrated or oxidized crystalline silicon. 
     
     
       38. The insulated substrate of claim 35, wherein the substrate comprises metal. 
     
     
       39. The insulated substrate of claim 38, wherein the metal substrate is selected from the group consisting of Cu, Cu alloy, Al, Al alloy, W, W alloy, Zn, Zn alloy, Ni and stainless steel. 
     
     
       40. The insulated substrate of claim 35, wherein the diamond-like carbon contains not more than 9 atm % of at least one element selected from the group consisting of silicon and germanium. 
     
     
       41. The insulated substrate of claim 35, wherein the thickness of the insulating layer is 10 Å to 2,000 Å. 
     
     
       42. The insulated substrate of claim 35, wherein the insulating layer has an electrical resistivity of not less than 10 8  .cm and a thermal resistance of 20 V/μm. 
     
     
       43. The insulated substrate of claim 35, wherein the heat conductivity of the insulated substrate is not less than 50 W/m.k. 
     
     
       44. The insulated substrate of claim 35, wherein the heat conductivity of the insulated substrate is not less than 100 W/m.k. 
     
     
       45. The insulated substrate of claim 35, wherein the surface Vickers hardness of the insulated substrate is not less than 500. 
     
     
       46. The insulated substrate of claim 35, wherein the surface Vickers hardness of the insulated substrate is not less than 1500. 
     
     
       47. The insulated substrate of claim 35, wherein the dielectric constant and dielectric loss at 1 MHz of the insulated substrate are not more than 20 and not more than 0.02, respectively. 
     
     
       48. The insulated substrate of claim 37, wherein the nitrated or oxidized crystalline silicon substrate is obtained by making through holes in a crystalline silicon substrate and thereafter nitrating or oxidizing the substrate. 
     
     
       49. The insulated substrate of claim 37, wherein the nitration or oxidation takes place in the crystalline silicon substrate at least to a depth of 0.1 μm from the surface of the substrate. 
     
     
       50. The insulated substrate of claim 37, wherein the nitration or oxidation takes place in the crystalline silicon substrate at least to a depth of 0.5 μm from the surface of the substrate. 
     
     
       51. The insulated substrate of claim 37, wherein the thickness of the insulating layer is 0.5 to 10 μm. 
     
     
       52. The insulated substrate of claim 37, wherein the thickness of the insulated layer is 1 to 10 μm. 
     
     
       53. The insulated substrate of claim 35, wherein the electrical conductivity of the insulating layer is not more than 10 -6  Ω -1  cm -1 . 
     
     
       54. The insulated substrate of claim 35, wherein the element of group IV A  is at least one element selected from the group consisting of Si, Ge and Sn. 
     
     
       55. The insulated substrate of claim 35, wherein a layer of hard carbon material having a thickness of 10 to 5,000 Å is formed on the interlayer, then a carbon film which substantially does not contain an element of group IVA is formed on the layer of hard carbon material. 
     
     
       56. The insulated substrate of claim 35, wherein the heat conductivity of the substrate is not less than 50 W/m.k. and the heat conductivity of the insulated substrate is not less than 45 W/m.k. 
     
     
       57. The insulated substrate of claim 35, wherein the electrical resistivity and dielectric breakdown voltage of the insulating layer are not less than 10 12  Ω·cm and not less than 100 V/um respectively. 
     
     
       58. The insulated substrate of claim 35, wherein the interlayer comprises an amorphous silicon compound containing at least one member selected from the group consisting of a-Si, a-Si x  C 1-x , a-Si x  N 1-x , a-Si x+y  C 1-x  N 1-y , a-Si x+y  C 1-x  O 1-y , a-Si x  Ge 1-x  and a-Si x+y  C 1-x  Ge 1-y  (wherein x and y satisfy the relationships of 0.001≦x≦1 and 0.001≦x+y≦1). 
     
     
       59. The insulated substrate of claim 58, wherein the amorphous silicon compound contains (A) at least one member selected from the group consisting of a-Si, a-Si x  C 1-x , a-Si x  N 1-x , a-Si x+y  C 1-x  N 1-y , a-Si x+y  C 1-x  O 1-y , a-Si x  Ge 1-x  and a-Si x+y  C 1-x  Ge 1-y  (wherein x and y satisfy the relationships of 0.001≦x≦1 and 0.001≦x+y≦1), and (B) at least one element selected from the group consisting of hydrogen and elements of the halogen group. 
     
     
       60. The insulated substrate of claim 35, wherein the thickness of the interlayer is 100 Å to 5 μm. 
     
     
       61. The insulated substrate of claim 35, wherein the thickness of the insulated layer is 1000 Å to 200 μm.